Vibration actuator and electric apparatus

ABSTRACT

A movable body wherein a pair of annular yokes including an opening at a center and a pair of weight parts including a through hole are stacked on a front and rear surfaces of a magnet having a circular plate shape in an axis direction, and another end portion of a connecting part that connects a pair of elastic support parts on one end portion side is disposed in the contiguous opening and through hole; and a fixing body wherein the movable body is housed in a cylindrical part, the movable body is supported with the pair of elastic support parts so as to be allowed to vibrate back and forth in the axial direction, and a pair of annular coils disposed radially outside the movable body is provided are provided, and the movable body is vibrated in the axial direction through energization of the coil.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is entitled to (or claims) the benefit of priority ofJapanese Patent Application No. 2021-109258, filed on Jun. 30, 2021, thedisclosure of which including the specification, drawings and abstractis incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a vibration actuator and an electricapparatus including the same.

BACKGROUND ART

In the related art, a vibration actuator as a vibration generationsource is mounted in electronic apparatuses having vibration functions.By driving the vibration actuator so as to transmit the vibration to theuser to make the user feel it, the electronic apparatus can providestimulation, provide notification of incoming call, and improve sense ofoperation and realism. The electronic apparatus is mainly hand-carryelectrical devices, including controllers (gamepads) of game machines,portable communication terminals such as smartphones, and portableinformation terminals such as tablet PCs. The vibration actuator mayalso be implemented in wearable devices worn on clothes, arms, etc.

As a vibration actuator with a structure that can be miniaturized andmounted in a mobile apparatus, a vibration actuator used for a pager,for example, is known, as shown in PTL 1.

In this vibration actuator, a pair of plate-shaped elastic bodies arearranged so that they face each other and are each supported by theopening edge of a cylindrical frame. In addition, the vibration actuatorhas a yoke with a magnet attached to the raised center portion of one ofthe spiral-shaped plate elastic bodies of the pair of plate elasticbodies, and the yoke is supported within the frame.

The yoke, together with a magnet, constitutes a circular magnetic fieldgenerator, and a coil is positioned within the magnetic field of thismagnetic field generator with the coil attached to the other plateelastic body. When a current of different frequency is given to the coilthrough an oscillation circuit in a switched manner, the pair of plateelastic bodies are selectively resonated to generate vibration, and theyoke vibrates in the centerline direction of the frame body within theframe body.

CITATION LIST Patent Literature PTL 1 Japanese Patent Publication No.3748637 SUMMARY OF INVENTION Technical Problem

By the way, it is desired that vibration actuators as vibrationgenerators be downsized while maintaining high output, as the productsin which they are mounted become smaller and smaller. In PTL 1, insidethe frame as the fixing body, the yoke as the movable body is supportedfrom one side of the vibration direction through the plate-shapedelastic body, and the coil disposed on the other side is disposed in therecess of the yoke so as to face the magnet in the radial direction.

Therefore, when the actuator is miniaturized, the assembly work iscomplicated and time-consuming, and the vibration output of thevibration actuator is also a problem.

In order to obtain a suitable vibration output in a miniaturizedvibration actuator, it is desired that the movable body be accuratelyformed to vibrate in a set vibration direction and its mass be easilyadjusted to ensure the desired vibration output.

An object of the present invention is to provide a vibration actuatorand an electric apparatus that can be manufactured with high dimensionalaccuracy and can be driven with a suitable vibration output whileachieving downsizing.

Solution to Problem

To achieve the above-mentioned object, a vibration actuator of anembodiment of the present invention includes: a movable body including amagnet having a circular plate shape, wherein a pair of annular yokesincluding an opening at a center and a pair of weight parts including athrough hole that is contiguous with the opening in an axial directionare stacked on a front surface and a rear surface of the magnet in theaxis direction, and another end portion of a connecting part thatconnects a pair of elastic support parts on one end portion side isdisposed in the opening and the through hole that are contiguous witheach other; and a fixing body including a cylindrical part configured tohouse the movable body, wherein with the pair of elastic support parts,the movable body is supported so as to be allowed to vibrate back andforth in the axial direction, and a pair of annular coils disposedradially outside the movable body is provided. The movable body isvibrated in the axial direction through energization of the coil.

An electric apparatus of an embodiment of the present invention is ahand-carry electric apparatus or a wearable electric apparatus. Thevibration actuator is mounted at a contact part for a user.

Advantageous Effects of Invention

According to the present invention, it is possible to achievemanufacturing with high dimensional accuracy and driving with a suitablevibration output while achieving downsizing.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating an external appearance of avibration actuator according to an embodiment of the present inventionas viewed from the front surface side;

FIG. 2 is a perspective view illustrating an external appearance of thevibration actuator according to the embodiment of the present inventionas viewed from the back side;

FIG. 3 is a longitudinal sectional view of the vibration actuator;

FIG. 4 is a diagram illustrating a state where the case and a drive unitinside it are disassembled in the vibration actuator;

FIG. 5 is a perspective view illustrating an external appearance of adrive unit;

FIG. 6 is an exploded perspective view illustrating a drive unit,illustrating a coil holding part, a movable body and an elastic supportpart;

FIG. 7 is a perspective view of a movable body to which an elasticsupport part is attached;

FIG. 8 is an exploded perspective view of a movable body to which anelastic support part is attached;

FIG. 9 is a diagram illustrating an outer surface of a coil assembly inwhich an outer yoke is detached from coil assembly in a drive unit;

FIG. 10 is a diagram illustrating a state where a coil is detached froma coil holding part in a coil assembly;

FIG. 11 is a bottom surface side perspective view of an outer yoke;

FIG. 12 is a top surface side perspective view of case main body;

FIG. 13 is a bottom surface side perspective view of a lid part;

FIG. 14 is a diagram schematically illustrating a magnetic circuit ofthe vibration actuator;

FIG. 15 is a diagram illustrating an operation of an actuator main body,and a diagram illustrating a vibration state where a movable body islocated on a first amplitude position on the top surface side;

FIG. 16 is a diagram illustrating an operation of the actuator mainbody, and a diagram illustrating the vibration state where the movablebody is located at a second amplitude position on the top surface side;

FIG. 17 is a diagram illustrating an operation of the actuator mainbody, and a diagram illustrating the vibration state where the movablebody is located at the first amplitude position on the bottom surfaceside;

FIG. 18 is a diagram illustrating an operation of the actuator mainbody, and a vibration state where the movable body is located at thesecond amplitude position on the bottom surface side;

FIG. 19 is a diagram schematically illustrating a magnetism balance ofthe vibration actuator in a non-vibration state of the presentembodiment;

FIG. 20 is a diagram illustrating a magnetism balance in a non-vibrationstate of a vibration actuator as a comparative example;

FIG. 21A and FIG. 21B are diagrams illustrating an operation of avibration actuator as a comparative example, FIG. 21A is a diagramillustrating a vibration state where the movable body is located on thefirst amplitude position on the top surface side, and FIG. 21B is adiagram illustrating the vibration state where the movable body islocated at the second amplitude position on the top surface side;

FIG. 22 is a diagram illustrating an example of an electric apparatus inwhich the vibration actuator of the present embodiment is mounted; and

FIG. 23 is a diagram illustrating an example of an electric apparatus inwhich the vibration actuator of the present embodiment is mounted.

DESCRIPTION OF EMBODIMENTS

An embodiment of the present invention is elaborated below withreference to the accompanying drawings.

General Configuration of Vibration Actuator

FIG. 1 is a perspective view illustrating an external appearance of avibration actuator according to an embodiment of the present inventionas viewed from the front surface side, and FIG. 2 is a perspective viewillustrating an external appearance of the vibration actuator accordingto the embodiment of the present invention as viewed from the back side.In addition, FIG. 3 is a longitudinal sectional view of the vibrationactuator. In addition, FIG. 4 is a diagram illustrating a state wherethe case and the drive unit inside it are disassembled in the vibrationactuator. Note that in the present embodiment the “upper” side and the“lower” side are used for the sake of ease of the understanding, andmean one side and the other side of the vibration direction of themovable body in the vibration actuator. That is, when the vibrationactuator is mounted to the electric apparatus (see FIG. 22 and FIG. 23), it may be disposed upside down or left to right.

Vibration actuator 1 is mounted as a vibration generation source in anelectronic apparatus such as a mobile game terminal apparatus (forexample, game controller GC illustrated in FIG. 22 ) as an electricapparatus, and implements the vibration function of the electronicapparatus. This electronic apparatus includes a mobile apparatus such asa smartphone (for example, mobile terminal M illustrated in FIG. 23 ).Vibration actuator 1 is mounted in each apparatus such as a mobile gameterminal apparatus and a mobile apparatus, and is driven into vibrationto provide the user with notification of an incoming call, and a senseof operation and realism.

As illustrated in FIG. 1 and FIG. 2 , vibration actuator 1 is avibrating member including case 10 with a columnar shape as a whole. Incase 10, both end surface parts in the axial direction (vibrationdirection) are formed in a protruding shape, and the center portion ofthe end surface part is formed in a flat shape.

In the present embodiment, case 10 is a hollow cylinder including casemain body 11 with a bottomed cylindrical shape and lid part 12 asillustrated in FIG. 3 and FIG. 4 . Details of case 10 will be describedlater.

As illustrated in FIG. 3 and FIG. 4 , vibration actuator 1 is composedof drive unit 15 including movable body 20 configured to vibrate andhoused in case 10. When movable body 20 moves, vibration actuator 1itself functions as a vibrating member. In the present embodiment, driveunit 15 has a columnar shape as a whole, and its central axis (notillustrated in the drawing) is parallel to or coincides with the centralaxis (not illustrated in the drawing) of case 10 with a similar columnarshape. In addition, in the present embodiment, the vibration directionof movable body 20 is a straight line direction including the Fdirection and the −F direction (see FIG. 14 ) extending along thedirection of the central axis of columnar drive unit 15.

Vibration actuator 1 includes movable body 20 including magnet 21, firstyoke 23 and second yoke 25, fixing body 40 including the coil (a pair ofcoils 61 and 62), and plate-shaped elastic support parts 81 and 82 thatsupport movable body 20 such that movable body 20 can move back andforth with respect to fixing body 40.

FIG. 5 is a perspective view illustrating an external appearance ofdrive unit 15. More specifically, FIG. 5 is a perspective view as viewedfrom the terminal tying part side. FIG. 6 is an exploded perspectiveview of a drive unit illustrating a coil holding part, a movable bodyand an elastic support part.

Drive unit 15 illustrated in FIG. 3 to FIG. 6 includes coil holding part42, outer yoke 50, movable body 20, and elastic support parts 81 and 82.Note that together with coils 61 and 62, coil holding part 42 makes up acoil assembly which is a part of a fixing body, and the coil assembly isa part of the fixing body together with outer yoke 50. Through elasticsupport parts 81 and 82 disposed opposite to each other with a spacetherebetween in the axial direction (vibration direction), drive unit 15supports movable body 20 disposed in coil holding part 42 such that itcan vibrate in a suspended manner with respect to coil holding part 42.

Note that through the terminal tying part (connection part) 43 exposedat its outer peripheral surface, i.e., the outer peripheral surface ofcoil holding part 42, drive unit 15 is connected to an external deviceto receive the power supply of the external device.

Movable Body 20

As illustrated in FIG. 3 and FIG. 6 , movable body 20 is disposed insidecylindrical coil holding part 42 of fixing body 40 with a spacetherebetween in the circumferential direction. Movable body 20 has acolumnar shape, and is connected with the inner periphery part ofelastic support parts 81 and 82 at both end portions (upper and lowerend portions) separated in the axial direction, i.e., the vibrationdirection. Elastic support parts 81 and 82 are attached to cover theopenings of cylindrical coil holding part 42. Movable body 20 issupported so as to be movable back and forth in the axial directionalong inner peripheral surface 42 a of coil holding part 42.

FIG. 7 is a perspective view of a movable body to which an elasticsupport part is attached, and FIG. 8 is an exploded perspective view ofa movable body to which an elastic support part is attached.

As illustrated in FIG. 3 and FIG. 6 to FIG. 8 , movable body 20 includesmagnet 21, a pair of movable yokes (for example, first yoke 23 andsecond yoke 25), a pair of weight parts (weight part 27 and weight part29) and a pair of connecting parts (first connecting part 31 and secondconnecting part 33).

In the present embodiment, in movable body 20, magnet 21 is disposed atthe center portion in the vibration direction, i.e., the center ofmovable body 20. On both sides of this magnet 21 in the vibrationdirection (front surface 21 a side and rear surface 21 b side, and thevertical direction in each drawing), first yoke 23 and second yoke 25,weight parts 27 and 29 and connecting parts 31 and 33 are provided in asymmetric manner with respect to magnet 21. For example, first yoke 23and second yoke 25, and weight parts 27 and 29 are provided in acontinuous manner on both sides of magnet 21 in the vibration direction.Connecting parts 31 and 33 are inserted and joined to first yoke 23 andweight part 27, and second yoke 25 and weight part 29, respectively. Inmovable body 20, weight parts 27 and 29 are stacked to magnet 21, firstyoke 23 and second yoke 25 in such a manner as to be disposed at aposition that does not face outer yoke 50 in fixing body 40 when movablebody 20 is at the maximum amplitude position in the vibration direction(see FIG. 16 and FIG. 18 ). In addition, weight parts 27 and 29 arecomposed of non-magnetic substance. Thus, the magnetic circuit can beformed in a compact size by suppressing the increase in the size of theconfiguration of the magnetic circuit of vibration actuator 1. Inaddition, since weight parts 27 and 29 are composed of a non-magneticsubstance that does not affect the magnetic circuit size, the highdegree of freedom in design of weight parts 27 and 29 can be achievedwhile obtaining desired vibration characteristics of movable body 20.

In movable body 20, outer peripheral surface 20 a at the center portion,or more specifically, the outer peripheral surface of magnet 21 andfirst yoke 23, second yoke 25, is disposed in an opposite manner with apredetermined distance therebetween inside inner peripheral surface 42 aof coil holding part 42.

Magnet 21

As illustrated in FIG. 6 to FIG. 8 , magnet 21 has a solid columnarshape (plate shape) magnetized in the vibration direction. For example,in magnet 21, front and rear surfaces 21 a and 21 b separated in thevibration direction have different respective polarities. In addition,in the present embodiment, magnet 21 is formed in a columnar shape(which may be referred to as circular plate shape) whose diameter(lateral width) is greater than the length (height) in the vibrationdirection. Magnet 21 is a neodymium sintering magnet, for example.

With respect to the coil held by coil holding part 42 (the pair of coils61 and 62)(details are described later), magnet 21 is disposed at aposition inside the coil (the pair of coils 61 and 62) in the radialdirection with a distance therebetween. Here, “radial direction” is alsoa direction orthogonal to the axis direction (vibration direction) ofthe coil (the pair of coils 61 and 62). In other words, on the outsidein the radial direction, magnet 21 is disposed opposite to the centerposition of the vibration direction at the inner peripheral surface ofcoil holding part 42. Note that the pair of coils 61 and 62 is alsoreferred to as “coils 61 and 62”.

The “distance” in the radial direction is the distance between coils 61and 62 and magnet 21 in the state where cylindrical main body part 422where coils 61 and 62 are wound is located between coils 61 and 62 andmagnet 21 on the inside in the radial direction of coils 61 and 62. Inaddition, the distance is a distance with which they can move withoutmaking contact with each other in the vibration direction of movablebody 20. The “distance” in the embodiment means a predetermined distancebetween magnet 21 and coil holding part 42 (especially cylindrical mainbody part 422) illustrated in FIG. 3 .

Magnet 21 may have shapes other than the solid columnar shape, such ascylindrical shapes and plate shapes, as long as it is disposed with thetwo magnetization surfaces facing in the extending direction of the axisof coils 61 and 62 inside coils 61 and 62. In addition, it is desirablethat the center of magnet 21 in the axis direction coincide with thecenter of movable body 20 in the axis direction.

First Yoke 23 and Second Yoke 25

First yoke 23 and second yoke 25 are magnetic substances, and are fixedto front and rear surfaces 21 a and 21 b of magnet 21, respectively.Each of first yoke 23 and second yoke 25 is formed in an annular shape.Each of first yoke 23 and second yoke 25 has an outer peripheral surfacewith the same diameter as magnet 21.

First yoke 23 and second yoke 25 make up a magnetic circuit togetherwith magnet 21, the coil (the pair of coils 61 and 62) and outer yoke50, and vibration actuator 1. First yoke 23 and second yoke 25concentrate the magnetic flux of magnet 21, efficiently transmit itwithout causing leakage, and effectively distribute the magnetic fluxflowing between magnet 21 and the coil (the pair of coils 61 and 62).First yoke 23 and second yoke 25 are formed of steel electrolytic coldcommercial (SECC) or the like, for example.

In addition, in addition to the function as a part of the magneticcircuit, first yoke 23 and second yoke 25 may have a function as a mainbody of movable body 20, a function of positioning and fixing connectingparts 31 and 33 to magnet 21, and a function as a weight, in movablebody 20.

In the present embodiment, first yoke 23 and second yoke 25 are formedin annular plate shape with the same surface shape and the same outerdiameter as magnet 21. First yoke 23 and second yoke 25 are fixed tomagnet 21 such that the outer peripheral surface is flush with the outerperipheral surface of the magnet, and make up outer peripheral surface20 a of movable body 20 together with the outer peripheral surface ofmagnet 21.

In the present embodiment, first yoke 23 and second yoke 25 are similarmembers that are symmetrically disposed at front and rear surfaces 21 aand 21 b of magnet 21 (upper and lower surfaces) around magnet 21 withmagnet 21 therebetween. Note that first yoke 23 and second yoke 25 maybe firmly fixed by being attracted by magnet 21, or may be fixed tomagnet 21 with an anaerobic adhesive agent or a heat curable adhesiveagent such as epoxy resin, for example.

Yoke openings 232 and 252 are provided at center portions of first yoke23 and second yoke 25, respectively. Connecting parts 31 and 33 (alsoreferred to as first connecting part 31 and second connecting part 33)are inserted to yoke openings 232 and 252. For example, connecting part33 may be internally fitted to yoke openings 232 and 252, and may bejoined after the insertion.

Yoke openings 232 and 252 are provided such that the axes of connectingparts 31 and 33, or in other words, the central axes of elastic supportparts 81 and 82 described later are located on the central axis ofmovable body 20. Note that while yoke openings 232 and 252 are formedwith sized fitted with each other in accordance with the external shapesof connecting parts 31 and 33, this is not limitative. Yoke openings 232and 252 may be supported so as be fixed and located on the axis ofmovable body 20 in contact with the outer peripheral surface of theinserted connecting parts 31 and 33 at three or four points. Inaddition, yoke openings 232 and 252 may be formed in recessed shapeswithout extending through the axial direction, and connecting parts 31and 33 may be joined in the recesses.

In a in a non-vibration state, first yoke 23 and second yoke 25 arelocated inside (on the inside in the radial direction) the coil (thepair of coils 61 and 62) so as to face respective coils (the pair ofcoils 61 and 62) in the direction orthogonal to the axis direction ofthe coil (the pair of coils 61 and 62). Preferably, in a non-vibrationstate of movable body 20, first yoke 23 and second yoke 25 are locatedon the inside (on the inside in the radial direction) of the pair ofcoils 61 and 62 so as to face the centers, in the vibration direction,of the pair of coils 61 and 62, respectively, in the directionorthogonal to the vibration direction.

In addition, preferably, in the present embodiment, first yoke 23 andsecond yoke 25 are configured such that the height position of the topsurface of first yoke 23 on the upper side of magnet 21 is located onthe lower side (center side) of the upper end position of upper sidecoil 61. Additionally, it is preferable that the height position of thebottom surface of second yoke 25 of magnet 21 be located on the upperside (center side) of the lower end position of lower side coil 62.

In this manner, together with magnet 21 and coils 61 and 62 and outeryoke 50, first yoke 23 and second yoke 25 serve as a magnetic circuitincluding a suitable magnetic path with high magnetic efficiency withsmall magnetic flux leakage.

Weight Parts 27 and 29

Weight parts 27 and 29 are provided to first yoke 23 and second yoke 25sandwiching magnet 21 so as to sandwich first yoke 23 and second yoke25.

Weight parts 27 and 29 are disposed in a symmetric manner so as tosandwich magnet 21, first yoke 23 and second yoke 25, and increase thevibration output of movable body 20.

Preferably, weight parts 27 and 29 are configured with a material withhigh specific gravity. Weight parts 27 and 29 are formed of a material,such as a tungsten (19.3 g/cm³), with higher specific gravity than firstyoke 23 and second yoke 25. Preferably, weight parts 27 and 29 areformed of a material with a specific gravity (a specific gravity ofabout 16 to 19 g/cm³, for example) higher than that of a material suchas a silicon steel sheet (the specific gravity of the steel sheet is7.70 to 7.98 g/cm³). Tungsten may be provided as the material of weightparts 27 and 29, for example. In this manner, even when the dimension ofthe external shape of movable body 20 is set for the design, the mass ofmovable body 20 can be relatively easily increased, and a desiredvibration output as sufficient sensory vibration for the user can beachieved.

The mass of weight parts 27 and 29 can be changed by changing the sizein accordance with the vibration output of movable body 20. The outerdiameters of weight parts 27 and 29 are smaller than the outer diametersof first yoke 23 and second yoke 25. In this manner, when movable body20 vibrates, movable body 20 less easily makes contact with elasticsupport parts 81 and 82 and thus can favorably vibrate. In this manner,a high vibration output can be ensured while downsizing vibrationactuator 1.

Each of weight parts 27 and 29 is formed in an annular shape. Throughholes 272 and 292 of weight parts 27 and 29 are formed with the samediameter and the same axes of yoke openings 232 and 252 of first yoke 23and second yoke 25, while they may have different diameters.

Connecting parts 31 and 33 are inserted to through holes 272 and 292 ofweight parts 27 and 29.

Together with yoke openings 232 and 252, through holes 272 and 292function as positioning parts for positioning to the same axis as theaxis of movable body 20 when attaching connecting parts 31 and 33 to themagnet. While weight parts 27 and 29 are continuously provided for eachfirst yoke 23 and second yoke 25 in the present embodiment, two, orthree or more, weight parts 27 and 29 may be continuously provided foreach first yoke 23 and second yoke 25. While it is preferable to usemembers with the same configuration for weight parts 27 and 29, this isnot limitative as long as they have the same function and mass.

Connecting Parts 31 and 33

Connecting parts 31 and 33 connect magnet 21, first yoke 23 and secondyoke 25 to elastic support parts 81 and 82.

In movable body 20, connecting parts 31 and 33 make up the end portionon both sides in the vibration direction, i.e., end portions located onthe both sides and separated from magnet 21 in the vibration direction.

In the present embodiment, connecting parts 31 and 33 are columnarmembers disposed along the central axis of movable body 20, and areinterposed between first yoke 23 and second yoke 25, and elastic supportparts 81 and 82.

Connecting parts 31 and 33 are disposed to protrude from the respectivecenter portions of front and rear surfaces 21 a and 21 b of magnet 21,and are inserted to first yoke 23, second yoke 25, and weight parts 27and 29. Connecting parts 31 and 33 are fixed to first yoke 23, secondyoke 25, and weight parts 27 and 29. Further, connecting parts 31 and 33may be fixed to magnet 21, and are disposed to protrude from weightparts 27 and 29.

Connecting parts 31 and 33 include connection main bodies 312 and 332provided on one end portion side and fixed to a member making up movablebody 20, and support fixing parts 314 and 334 provided on the other endportion side and provided at the other end portion of connection mainbodies 312 and 332.

Connection main bodies 312 and 332 have shapes that can be inserted toyoke openings 232 and 252 of first yoke 23 and second yoke 25 andthrough holes 272 and 292 of weight parts 27 and 29. Since yoke openings232 and 252 and through holes 272 and 292 of the present embodiment havethe same diameter, connection main bodies 312 and 332 are formed incolumnar shapes corresponding to yoke openings 232 and 252 and throughholes 272 and 292. In the present embodiment, connection main bodies 312and 332 are positioned by being inserted to yoke openings 232 and 252and through holes 272 and 292, and fixed to magnet 21, first yoke 23 andsecond yoke 25, weight parts 27 and 29 and the like.

Connection main bodies 312 and 332 may be fixed to both of first yoke 23and second yoke 25 and weight parts 27 and 29 through press-fitting.Connecting parts 31 and 33 may be fixed to first yoke 23 and second yoke25 and weight parts 27 and 29 by bonding using or not using an anaerobicadhesive agent or a heat curable adhesive agent such as epoxy resin, forexample.

Connection main bodies 312 and 332 may be joined to magnet 21 in contactwith it at the other end surface that faces magnet 21. Connection mainbodies 312 and 332 are disposed such that the central axis thereof andthe axis line of movable body 20 coincide with each other, and thatconnection main bodies 312 and 332 protrude to both sides in thevibration direction along its axis line.

Support fixing parts 314 and 334 join movable body 20 to elastic supportparts 81 and 82 through connection main bodies 312 and 332 of connectingparts 31 and 33.

Support fixing parts 314 and 334 are portions protruding from thesurface of the one end portion side in the axial direction (vibrationdirection) at connection main bodies 312 and 332, with a smaller outerdiameter than the outer diameter of connection main bodies 312 and 332.Note that recesses 316 and 336 are provided around this protrudingportion. Recesses 316 and 336 are annular groove parts that surroundsupport fixing parts 314 and 334. Recesses 316 and 336 may function as abonding material retainer or a welding material retainer at the time ofjoining with the inner periphery part of elastic support parts 81 and82, an engaging object portion at the time of caulking, and the like forexample. In such cases, recesses 316 and 336 can be firmly joined tomovable body 20 and elastic support parts 81 and 82.

More specifically, support fixing part 314 makes up one end portion ofmovable body 20 in the vibration direction, i.e., the upper end portionof movable body 20, and is joined to inner periphery part 802, which isan internal diameter side end portion of the upper leaf spring, which iselastic support part 81. On the other hand, support fixing part 334makes up the other end portion of movable body 20 in the vibrationdirection, i.e., the lower end portion of movable body 20, and is joinedto inner periphery part 802, which is the internal diameter side endportion of the lower leaf spring, which is elastic support part 82.

In the state where support fixing parts 314 and 334 are internallyfitted and joined to the inner periphery parts 802 and 802 of elasticsupport parts 81 and 82, the surface of one end portion side ofconnection main bodies 312 and 332 around support fixing parts 314 and334 face inner periphery parts 802 and 802. Note that connection mainbodies 312 and 332 may be joined to elastic support parts 81 and 82joined to support fixing parts 314 and 334 at the portion around supportfixing parts 314 and 334 at the other end portion thereof. For example,connection main bodies 312 and 332 and elastic support parts 81 and 82may be joined with an adhesive agent, or joined through welding or thelike. In addition, together with another member such as a rivet,connection main bodies 312 and 332 may be joined to elastic supportparts 81 and 82 with elastic support parts 81 and 82 therebetween. Inthis manner, connection main bodies 312 and 332 and inner peripheryparts 802 and 802 may be reliably joined to each other, and elasticsupport parts 81 and 82 and movable body 20 can be more reliably joined.

Further, elastic support parts 81 and 82 and support fixing parts 314and 334 may be connected through caulking and the like, or throughwelding and/or bonding combined with caulking. Note that connectingparts 31 and 33 are formed of a copper sintered material, for example.Connecting parts 31 and 33 may be formed of a metal functioning as aweight of movable body 20.

In movable body 20, connecting parts 31 and 33 are disposed at positionsoutside the magnetic circuit including magnet 21, first yoke 23 andsecond yoke 25. In this manner, the installation space of the pair ofcoils 61 and 62 is not limited, i.e., the distance between the magneticcircuit on the movable body side (magnet 21 and first and second yokes23 and 25) and the pair of coils 61 and 62 is not increased, and thus,electromagnetic conversion efficiency is not reduced. In this manner,the weight of movable body 20 can be favorably increased, and a highvibration output can be achieved.

In addition, in the case where a function as a weight is provided toconnecting parts 31 and 33, the vibration output of vibration actuator 1can be adjusted through mass adjustment with weight parts 27 and 29.

Fixing Body 40

As illustrated in FIG. 3 , fixing body 40 includes the pair of coils 61and 62, and houses movable body 20 including magnet 21 on the inside inthe radial direction of the pair of coils 61 and 62. Fixing body 40movably supports movable body 20 in the axis direction (which is thevibration direction and the coil axial direction) of movable body 20through elastic support parts 81 and 82.

FIG. 9 is a diagram illustrating an outer surface of a coil assembly inwhich an outer yoke is detached from coil assembly in a drive unit, andFIG. 10 is a diagram illustrating a state where a coil is detached froma coil holding part in a coil assembly.

As illustrated in FIG. 3 to FIG. 6 , FIG. 9 , and FIG. 10 , fixing body40 includes case 10, the coil (the pair of coils 61 and 62), coilholding part 42 that holds coils 61 and 62, and outer yoke 50. Note thattogether with movable body 20 and elastic support parts 81 and 82, thiscoil assembly makes up drive unit 15.

Fixing body 40 need not include case 10 as long as it has aconfiguration of holding the pair of coils 61 and 62 and movablysupporting movable body 20 through elastic support parts 81 and 82.

Coil holding part 42 is a cylindrical member formed of a resin such asphenol resin and poly butylene terephthalate (PBT). In the presentembodiment, coil holding part 42 is formed of a material containingphenol resin such as highly flame-retardant Bakelite.

Note that with coil holding part 42 composed of a material containingphenol resin, flame retardancy is increased, and the safety in thedriving can be improved even when heat is generated by Joule heat due tothe current supplied to the coil (the pair of coils 61 and 62) heldtherein. In addition, since the dimensional accuracy and the positionalaccuracy of the coil (the pair of coils 61 and 62) are increased, thenon-uniformity of vibration characteristics can be reduced.

As illustrated in FIG. 9 and FIG. 10 , coil holding part 42 includescylindrical main body part 422, flange parts 426 to 428 protrudingradially outward from the outer peripheral surface of cylindrical mainbody part 422, layout part 41 including terminal drawing part 46 andconnecting groove part 47, and engaging protruding parts 44 and 45.

Coil holding part 42 is formed in a coil bobbin shape with cylindricalmain body part 422 and flange parts 426 to 428. Coil holding part 42includes coil attaching portions 42 b and 42 c where the coil (the pairof coils 61 and 62) is wound between flange parts 426 to 428.

Cylindrical main body part 422 includes inner peripheral surface 42 athat faces the outer peripheral surface of movable body 20 with apredetermined distance therebetween on the inside in the radialdirection of the pair of coils 61 and 62. This predetermined distanceallows movable body 20 to move in the vibration direction without makingcontact with inner peripheral surface 42 a.

Cylindrical main body part 422 is located between magnet 21 and the pairof coils 61 and 62, thus preventing the contact between magnet 21 andthe pair of coils 61 and 62. Cylindrical main body part 422 guidesmovable body 20 such that it is movable back and forth along innerperipheral surface 42 a.

That is, at the time of driving of movable body 20, cylindrical mainbody part 422 functions as a protecting wall part that protects movablebody 20 striking the pair of coils 61 and 62. The thickness ofcylindrical main body part 422 is a thickness with a strength with whichthe pair of coils 61 and 62 on the outer circumference side are notaffected even when the moving movable body 20 makes contact with it.

Coil attaching portions 42 b and 42 c are provided in recessed shapes inthe outer peripheral surface of cylindrical main body part 422.

More specifically, coil attaching portions 42 b and 42 c (see FIG. 10 )are formed with the outer peripheral surface of cylindrical main bodypart 422 and flange parts 426 to 428, so as to open to the outside inthe radial direction from the outer peripheral surface of cylindricalmain body part 422 to the outer circumference side.

Coil attaching portions 42 b and 42 c are defined by flange parts 426 to428. The pair of coils 61 and 62 is wound at coil attaching portions 42b and 42 c. The pair of coils 61 and 62 is wound between flange parts(also referred to as “end flange part”) 427 and 428 with flange part 426at the center (hereinafter referred to also as “the center flange part”)therebetween in the vibration direction.

Coils 61 and 62 in coil attaching portions 42 b and 42 c are disposed atpositions aligned in the coil axial direction so as to surround theouter peripheral surfaces of first yoke 23 and second yoke 25 of movablebody 20 (the outer peripheral surfaces of first yoke 23 and second yoke25 and magnet 21).

Center flange part 426 is provided in an annular shape protrudingradially outward from the outer peripheral surface of cylindrical mainbody part 422, and includes an annular outer periphery part. Note thatlayout part 41 for laying out the winding is provided at a part of theouter periphery part of center flange part 426.

The diameter of center flange part 426 excluding terminal drawing part46, i.e., the diameter of outer periphery part 426 a is smaller than themaximum diameter of other flange parts (end flange parts 427 and 428).In this manner, at the outer peripheral surface of coil holding part 42,recessed part 420 is formed at a center portion in the vibrationdirection and at the opening edge part of coil attaching portions 42 band 42 c (see FIG. 9 and FIG. 10 ).

In this manner, outer yoke 50 is fit to recessed part 420, and outeryoke 50 covers coil attaching portions 42 b and 42 c where coils 61 and62 are disposed in the state where its outer surface and the outersurfaces of end flange parts 427 and 428 flush with each other.

With terminal drawing part 46, layout part 41 processes the terminal(winding 63) of coils 61 and 62 to a state where it is connectable to anexternal device, and connecting groove part 47 guides winding 64 of thecoil. In this manner, the winding of the coil (for example winding 64)is laid out such that coil holding part 42 favorably holds coils 61 and62.

Terminal drawing part 46 includes terminal tying part 43. As illustratedin FIG. 9 and FIG. 10 , terminal tying part 43 functions as a connectorconnection part that ties winding 63 of the end portion of the windingthat couples the pair of coils 61 and 62, and connects it to theexternal device. Terminal tying part 43 connects the pair of coils 61and 62 and the external device (a power supply part such as a drivecontrol part) and achieves power supply from the external device to thepair of coils 61 and 62.

Terminal tying part 43 is a conductive member provided upright at coilholding part 42, or more specifically, at the outer periphery part ofcylindrical main body part 422. Terminal tying part 43 includes a rodmember for tying the winding of the coil.

Terminal tying part 43 is provided by press-fitting the base end portionto terminal drawing part 46 provided upright at the outer periphery partof coil holding part 42, or more specifically, the outer peripheralsurface of center flange part 426 of coil holding part 42. Winding 63 ofthe end portion of the winding making up coils 61 and 62 is tied andconnected to terminal tying part 43, and this connecting portion isreliably joined with fillet 432 formed by soldering.

Terminal drawing part 46 protrudes from the outer peripheral surface ofcenter flange part 426 so as to have a predetermined length in theradial direction, a thickness in the vibration direction and a widthalong the circumferential direction at center flange part 426, andensures a press-fitting margin of terminal tying part 43. The width ofterminal drawing part 46 is parallel to the tangent to the outerperiphery of center flange part 426. Here, terminal drawing part 46 isformed in a cuboid shape, and, at its end surface, terminal tying part43, i.e., the both end portions of coils 61 and 62, are providedupright.

Terminal drawing part 46 ensures the press-fitting margin of terminaltying part 43, and thus terminal tying part 43 can be firmly held, andwhen assembling terminal tying part 43 to coil holding part 42, it canbe stably fixed.

Through terminal tying part 43, the terminal drawing part 46 draws outthe end portion of the winding of the coil that forms the coil (the pairof coils 61 and 62) to the outside of vibration actuator 1 and connectsit to the supply power source. Terminal drawing part 46 are insertedthrough outer yoke 50 so as to expose terminal tying part 43 to theoutside of outer yoke 50, and in turn, the outside of case 10.

Terminal tying part 43 is provided at terminal drawing part 46, andtherefore, even when outer yoke 50 makes contact with it and a load ofouter yoke 50 is applied thereto at the time of inserting terminaldrawing part 46 through outer yoke 50, it can be received by terminaldrawing part 46.

In this manner, is possible to prevent exertion of the load at the timeof attaching outer yoke 50 on terminal tying part 43 and the deformationof terminal tying part 43 due to the exertion of the load, and thus thevibration actuator can be stably manufactured. Note that a bonding partmay be provided at the outer peripheral surfaces of flange parts 426 to428 with the same outer diameter, and outer yoke 50 may be firmly fixedto each of flange parts 426 to 428 through the bonding part. With thisconfiguration, more stable vibration characteristics can be achieved.

In connecting groove part 47, winding 64 of the coil that connects thecoil (the pair of coils 61 and 62) is inserted. In connecting groovepart 47 of the present embodiment, the winding direction of the windingof the coil that forms coil 61 and coil 62 is inverted to oppositedirections between upper and lower parts of connecting groove part 47.

Connecting groove part 47 is formed to open radially outward at theouter periphery part of center flange part 426 and to extend throughalong the vibration direction. More specifically, connecting groove part47 includes bottom wall part 47 a that forms the bottom of a groove, andside wall part (one side wall part) 47 b remote from terminal tying part43 in bottom wall part 47 a.

Even when covered with outer yoke 50 in center flange part 426,connecting groove part 47 communicates coil attaching portions 42 b and42 c with each other in the vibration direction inside outer yoke 50 inthe radial direction. Connecting groove part 47 is disposed close to oradjacent to terminal drawing part 46.

As illustrated in FIG. 9 , connecting groove part 47 is a cutout portionwith a tilted bottom surface between the parallel wall surfaces of theside wall of terminal drawing part 46 and remote side wall part 47 b.The cutout portion has a function of locking the winding such that thewinding is not removed when one of coil 61 and coil 62 is wound anddisposed and then the other is wound and disposed after inverting thewinding direction. Connecting groove part 47 of the present embodimentis formed in a U-shape in plan view with bottom wall part 47 a as thebottom surface and the both side wall parts uprightly provided at bothends separated in the circumferential direction.

Thus, when the pair of coils 61 and 62 is disposed by winding thewinding of the coil around coil attaching portions 42 b and 42 c in aninverted manner between the upper and lower parts, winding 64 of thecoil is reliably engaged with connecting groove part 47 without beingremoved from connecting groove part 47. In this manner, winding 64 ofthe coil is favorably guided from one of coil attaching portions 42 band 42 c to the other with connecting groove part 47. Thus, assemblingof the pair of coils 61 and 62 to coil holding part 42 of a singlewinding of the coil can be easily performed.

Note that layout part 41 includes coil guide part 412 (see FIG. 10 ). Atcenter flange part 426, coil guide part 412 guides winding 63 of thecoil from terminal tying part 43 to the first winding position (forexample corner portion) of the coil winding portion (one of coilattaching portions 42 b and 42 c) of coil holding part 42.

Coil guide part 412 is provided at least at one of the upper and lowersurfaces (the surfaces separated in the vibration direction) of centerflange part 426. In the present embodiment, coil guide part 412 isformed stepwise with respect to terminal drawing part 46 in centerflange part 426 at the top surface portion of connecting groove part 47adjacent in one circumferential direction and the bottom surface portionof terminal drawing part 46.

Coil guide part 412 is an inclined part formed of the step of the upperand lower surfaces (the surfaces in the vibration direction) of centerflange part 426, and guides the winding of the coil to the bottomsurface side of coil attaching portions 42 b and 42 c, i.e., to theouter peripheral surface side of cylindrical main body part 422 fromterminal tying part 43.

For example, in FIG. 10 , after the winding of the coil is tied to oneof terminal tying part 43 (for example, terminal tying part 43 on theright side in the drawing), the coil is guided along coil guide part 412on the coil attaching portion 42 c side, and coil 62 is disposed bywinding it around coil attaching portion 42 c.

In this manner, in comparison with it is directly drawn from terminaltying part 43 to coil attaching portion 42 c, the winding position ofthe first winding can be stabilized and coil 62 can be favorablydisposed. Then, the winding of the end portion of coil 62 is guided tocoil attaching portion 42 b through connecting groove part 47, and thewinding of the coil is wound to coil attaching portion 42 b in thedirection opposite to coil 62 and thus, coil 61 is formed and disposed.

In this manner, when winding the winding of the coil extending fromterminal tying part 43 to coil attaching portions 42 b and 42 c, coilguide part 412 can stabilize the winding position of the first windingat coil attaching portions 42 b and 42 c, and one turn of the windingcan be reliably performed.

In this manner, tying of the winding to terminal tying part 43, formingof upper and lower coils 61 and 62, and finally tying to terminal tyingpart 43 can be performed by a series of flow to assemble vibrationactuator 1. In this manner, the coil forming step and the like can beeasily automated, and the vibration actuator with an efficient assemblystructure can be achieved.

End flange parts 427 and 428 are disposed at both end portions separatedin the axis direction of cylindrical main body part 422, and make up theupper and lower end portions of coil holding part 42.

End flange parts 427 and 428 (which are also collectively referred to as“both end flange part”) protrude radially outward from the outerperiphery of cylindrical main body part 422 to the both end portions inthe vibration direction. The outer periphery part of each of end flangeparts 427 and 428 has the same diameter portion as outer periphery part426 a of center flange part 426. The same diameter portion makes uprecessed part 420 and the outer peripheral surface of the same diameterportion makes contact with the inner peripheral surface of outer yoke50.

Outer yoke 50 is disposed at this recessed part 420, and thus outer yoke50 is positioned at the position surrounding the pair of coils 61 and62. In addition, outer yoke 50 is stably fixed to coil holding part 42by making contact with outer periphery part 426 a and the same diameterportion of end flange parts 427 and 428. In this manner, even in thecase where the height (vibration direction length) of outer yoke 50 islarge, it can be stably fixed by attaching it in accordance with theheight.

End flange parts 427 and 428 are formed in cylindrical shapes opening inthe direction separated from center flange part 426 (the verticaldirection in the present embodiment). In end flange parts 427 and 428,elastic support parts 81 and 82 are fixed at the end portions of theopening side, i.e., the upper and lower end portions.

Engaging protruding parts 44 and 45 are protruding parts providedupright in the vibration direction (vertical direction) at the upper andlower end portions of coil holding part 42, i.e., annular upper andlower opening edge surfaces (which are also referred to as “upper endsurface and lower end surface”) 427 a and 428 a of end flange parts 427and 428.

As illustrated in FIG. 3 and FIG. 4 , engaging protruding parts 44 and45 are engaged with engaging recess 127 of lid part 12 of case 10, andengaging recess 117 of case main body 11 (see FIG. 12 ). By engagingwith engaging recesses 127 and 117, engaging protruding parts 44 and 45set the positions of oil holding part 42 and lid part 12 and case mainbody 11 in the radial direction and the vibration direction, and set thepositions of elastic support parts 81 and 82 sandwiched by them in theradial direction.

Engaging protruding parts 44 and 45 are disposed opposite to top surfacepart 122 of lid part 12 and bottom part 114 of case main body 11, andend flange parts 427 and 428 receive top surface part 122 and bottompart 114 with elastic support parts 81 and 82 therebetween.

By fitting engaging protruding parts 44 and 45 to positioning groovepart 808, the positions of elastic support parts 81 and 82 with respectto coil holding part 42 are set. In this manner, the positions ofelastic support parts 81 and 82 in each individual drive unit 15 can beuniformed, and the positions of elastic support parts 81 and 82 withrespect to coil holding part 42 can be stably set. In this manner, themovement of elastic support parts 81 and 82 in the rotational directionis restricted, and, as a product, the variation in elastic support parts81 and 82 can be suppressed and stable characteristics can be achieved.

A plurality of engaging protruding parts 44 and 45 are provided aroundthe axis of coil holding part 42 at even interval.

In addition, the plurality of engaging protruding parts 44 and 45 engagewith the positioning groove part 808 of elastic support parts 81 and 82.In this manner, the positions of movable body 20 and coil holding part42 can be easily set by receiving the catching and friction of elasticsupport parts 81 and 82 at the time of insertion of movable body 20 intocoil holding part 42, and assembling it with good assemblability.

In addition, coil holding part 42 is housed and fixed in the case withupper and lower end portions engaging protruding parts 44 and 45 engagedwith engaging recesses 127 and 117 of case 10 so as to face the edge oflid part 12 and the edge of b bottom part 114.

Coils 61 and 62

In vibration actuator 1, the pair of coils 61 and 62 makes up a magneticcircuit used for generating the driving source together with magnet 21,first yoke 23 and second yoke 25 with the axis direction of the pair ofcoils 61 and 62 (magnet 21 magnetization direction) as the vibrationdirection.

The pair of coils 61 and 62 are energized at the time of driving(vibration), and makes up a voice coil motor together with magnet 21.Note that while the pair of coils 61 and 62 is provided in the presentembodiment, one coil or three or more coils may be provided as long as amagnetic circuit to be driven is configured in a similar manner, but itis preferable to provide even-numbered coils symmetrically disposedabout the vibration direction of the coil.

The pair of coils 61 and 62 is disposed at positions in a symmetricmanner about magnet 21 in the vibration direction with respect tomovable body 20 including magnet 21, first yoke 23 and second yoke 25and the like. It is preferable that the center of the length in thevibration direction of the coil, i.e., the center of the length betweenthe upper end of coil 61 and the lower end of coil 62 coincide (orsubstantially coincide) with the center of the length in the vibrationdirection of movable body 20 (in particular magnet 21) in the vibrationdirection.

In the present embodiment, the pair of coils 61 and 62 is composed ofsingle winding of the coil wound in the directions opposite to eachother, and current flows in opposite directions for coils 61 and 62 whenenergized.

The end portion of each of the pair of coils 61 and 62, i.e., the bothend portions of the winding of the coil making up the pair of coils 61and 62 are tied and connected to terminal tying part 43 of flange part426.

The coil (the pair of coils 61 and 62) is connected to the power supplypart (for example, drive control part 203 illustrated in FIG. 22 andFIG. 23 ) through terminal tying part 43. For example, the end portionof the coil (the pair of coils 61 and 62) is connected to thealternating current supply part through terminal tying part 43, and thealternating current power (AC voltage) is supplied from the alternatingcurrent supply part to the coil (the pair of coils 61 and 62). In thismanner, with the magnet, the coil (the pair of coils 61 and 62) cangenerate a thrust for moving toward or away from each other in the axisdirection.

As illustrated in FIG. 10 , in the coil (the pair of coils 61 and 62),the other end portion side of the winding of the coil whose one endportion is tied to one of terminal tying part 43 is guided to theposition where the first turn is formed in coil attaching portion 42 cat the step in coil guide part 412 on coil attaching portion 42 c side.The first turn is formed by wounding the winding counterclockwise at thefirst turning position, and then it is sequentially woundcounterclockwise so as to form coil 62.

Next, the winding of the other end portion side of coil 62 is guided tocoil attaching portion 42 b by connecting groove part 47 in theabove-mentioned manner, and sets it at the first turn position of coilattaching portion 42 b by reversing the winding direction in connectinggroove part 47. Thereafter, it is wound in the direction opposite tocoil attaching portion 42 c, here, in the clockwise direction, and thuswind coil 61 is formed in coil attaching portion 42 b. Note that whilethe coil (the pair of coils 61 and 62) is composed of single winding inthe present embodiment, this is not limitative, and it may be composedof separate coils (the pair of coils 61 and 62). In this configuration,in the case where the coils as separate members are composed of windingswound in the same direction, they supply respective currents ofdifferent directions at the time of driving.

Note that it is preferable that the coil axis of the pair of coils 61and 62 be disposed on the same axis as the axis of coil holding part 42or the axis of magnet 21.

In vibration actuator 1, the pair of coils 61 and 62 is formed in acylindrical shape by winding the coil line from the outside of coilholding part 42 to coil attaching portions 42 b and 42 c. In thismanner, coils 61 and 62 can be assembled without using self-weldingline, and cost reduction of the coil (the pair of coils 61 and 62)itself, and in turn, the cost reduction of the entire vibration actuatorare achieved.

Outer Yoke 50

FIG. 11 is a bottom surface side perspective view of an outer yoke. Asillustrated in FIG. 3 to FIG. 6 , FIG. 9 , and FIG. 11 , outer yoke 50is a cylindrical magnetic substance that surrounds the outer peripheralsurface of coil holding part 42 and is disposed at a position coveringthe pair of coils 61 and 62 on the outside in the radial direction.

As described above, outer yoke 50 makes up the fixing body side magneticcircuit together with the pair of coils 61 and 62 and makes up amagnetic circuit together with the movable body side magnetic circuit,i.e., magnet 21, first yoke 23 and second yoke 25. Outer yoke 50prevents leakage flux to the outside of vibration actuator 1 in themagnetic circuit.

In the magnetic circuit, outer yoke 50 can increase the electromagneticconversion efficiency by increasing the thrust constant. Outer yoke 50functions as a magnetic spring together with magnet 21 by using themagnetic attractive force of magnet 21. Thus, outer yoke 50 can reducethe stress when elastic support parts 81 and 82 serve as machinesprings, and can improve the durability of elastic support parts 81 and82.

In vibration actuator 1, when coils 61 and 62 are energized throughterminal tying part 43, movable body 20 moves back and forth in thevibration direction in case 10 with coils 61 and 62 and magnet 21 inconjunction with each other.

Outer yoke 50 is disposed such that the center of the length of outeryoke 50 in the vibration direction coincides with the center of magnet21 disposed inside in the vibration direction. With the shield effect ofthis outer yoke 50, leakage magnetic flux to the outside of thevibration actuator can be reduced.

The both end portions separated in the vibration direction in outer yoke50 are located at positions lower than the both end portions of movablebody 20 in the vibration direction when movable body 20 moves. That is,outer yoke 50 in the vibration direction, has a length that does notcover the both end portions of the movable range of a stacked member inwhich magnet 21, first yoke 23 and second yoke 25 are stacked.

Outer yoke 50 includes yoke main body 51 and a plurality of openings(first opening 53 and second opening 55) disposed at the same positionas yoke main body 51 in the vibration direction and dispersed in thecircumferential direction.

Yoke main body 51 is formed in a cylindrical shape, by using anelectricity zinc plating steel sheet (SECC) with excellent weldingperformance and corrosion resistance, for example.

In the present embodiment, yoke main body 51 has flexibility andincludes a slit that is parallel to the axial direction in a part of theperipheral wall. Yoke main body 51 has a C-cylindrical shape in plancross-sectional view. In yoke main body 51, at the time of attaching tothe outer periphery coil holding part 42, coil holding part 42 isdisposed into yoke main body 51 by widening the part between endportions 52 making up the slit. Next, the deformation of yoke main body51 is reset, and yoke main body 51 is fit to recessed part 420 of theouter periphery of coil holding part 42, and thus, yoke main body 51 isinserted outside coil holding part 42.

A plurality of openings 53 and 55 is provided at yoke main body 51 suchthat edges that are opposite to each other in the vibration directionare disposed at the same position between openings 53 and 55. In yokemain body 51, the plurality of openings 53 and 55 open at positionsopposite to each other with the axis of outer yoke 50 at the center, forexample.

Each of the plurality of openings 53 and 55 is provided at the centerportion in the vibration direction in yoke main body 51. The pluralityof openings 53 and 55 may be provided at even intervals in thecircumferential direction in yoke main body 51.

In the present embodiment, the plurality of openings 53 and 55 is formedin rectangular shapes in yoke main body 51 that are defined by parallelside portions separated in the circumferential direction in thecircumferential direction, and are defined by upper and lower portionsseparated into symmetrical shapes in the vibration direction in thevibration direction.

The plurality of openings 53 and 55 includes first opening 53 forinserting a wiring for connecting the external device and coils 61 and62, and second opening 55 provided at a predetermined position based onthe position of first opening 53. Note that opening 53 is provided toextend in the circumferential direction at the center portion of theslit of yoke main body 51. The upper and lower portions that defineopening 53 are formed of end portions 52 protruding in thecircumferential direction to face each other in the circumferentialdirection in yoke main body 51.

Terminal drawing part 46 is inserted to opening 53. In this manner theterminal tying part (wiring) 43 connected to coils 61 and 62 passesthrough opening 53, and terminal tying part (wiring) 43 is protruded andexposed to the outside of outer yoke 50 so as to be able to connect tothe external device.

In addition, opening 53 functions as a stopper for stopping the rotationof outer yoke 50 in the circumferential direction with respect to coilholding part 42 by being fitted to terminal drawing part 46.

In opening 53, cutout part 533 with a shape cut out to widen opening 53is provided at edges diagonally disposed at the left and right sideportions that define opening 53. That is, opening 53 has a cut out shapein which the portions of the edges extending along the vibrationdirection are shifted in the circumferential direction.

The end portion of the winding connected to terminal tying part 43 isset in cutout part 533. When outer yoke 50 is fit to recessed part 420of coil holding part 42, terminal drawing part 46 is disposed to closeopening 53 in opening 53. At this time, in cutout part 533 cut out witha shift in the circumferential direction, the winding for connectingterminal tying part 43 of terminal drawing part 46 and coils 61 and 62inside outer yoke 50 is set without being blocked. Thus, outer yoke 50can be favorably attached to coil holding part 42 without beinginterfered by the winding of the coil.

In outer yoke 50, the left and right side portions that define opening53 in the circumferential direction may be formed to sandwich terminaldrawing part 46. In this case, the protruding side portion adjacent tocutout part 533 can hold terminal drawing part 46 by pressing terminaldrawing part 46 from the both sides in the circumferential direction. Inthis manner, outer yoke 50 can reliably attach, to coil holding part 42,terminal drawing part 46 sandwiched in the circumferential direction.

In addition, opening 53 is divided by terminal drawing part 46 into tworegions separated in the vibration direction, and belt-shaped openingregions extending in the circumferential direction and communicated withcutout part 533 are formed on both (upper and lower) sides in thevibration direction with respect to terminal drawing part 46. In thebelt-shape region including cutout part 533, the winding for connectingterminal tying part 43 and coil attaching portions 42 b and 42 c isfavorably disposed.

Opening (second opening) 55 is provided at a position opposite toopening 53 with respect to the center of the radial direction. In yokemain body 51, opening 55 is formed at a position opposite to opening 53,for example. Opening 55 is defined by the upper, lower, left and rightside portions and extended in the circumferential direction in arectangular shape that is substantially the same shape as that ofopening 53.

The width of upper and lower portions 55 a and 55 b that define opening55 in the vibration direction is substantially the same as the width ofthe upper and lower portions of opening 53 in the vibration direction.

Openings 53 and 55 form magnetic paths that are symmetric about the axisin the magnetic circuit, and keeps the balance of the generatedmagnetism. That is, in openings 53 and 55, movable body 20 and fixingbody 40 are equally attracted to each other in the vibration directionand the direction orthogonal to the vibration direction (radialdirection), i.e., the upper, lower, left and right directions. In thismanner, movable body 20 vibrates with respect to the fixing body in anequally attracted state in the radial direction.

In this manner, openings 53 and 55 are formed in the center portion ofouter yoke 50 in the vibration direction, with a shape that is longer inthe circumferential direction than in the vibration direction (verticaldirection). Since the upper and lower portions of outer yoke 50 areprovided on the upper and lower sides of openings 53 and 55, the leakageflux and imbalance of the magnetic attractive force in the magneticcircuit can also be minimized with a good balance.

Note that in the present embodiment, the upper and lower portions thatdefine opening 53 are divided by the slit sandwiched by end portion 52in the circumferential direction, which is different from aconfiguration in which no slit is provided at the upper and lowerportions. However, at the division at the upper and lower portions inopening 53, the distance between end portions 52 facing each otherthrough the cutout in the circumferential direction is small, and thusit has a function similar to that of the upper and lower portions withno slit, and has similar effects in terms of a magnetic circuit.

While openings 53 and 55 are provided at opposite two locations facingthe center portion in the vertical direction (vibration direction) inouter yoke 50 in the present embodiment, two or more openings may beprovided as long as they are formed at even intervals about the axis ofouter yoke 50 at the center.

Elastic Support Parts 81 and 82

As illustrated in FIG. 3 to FIG. 9 , elastic support parts 81 and 82support movable body 20 with respect to fixing body 40 so as to bemovable back and forth in the vibration direction.

Elastic support parts 81 and 82 sandwich movable body 20 in thevibration direction of movable body 20, and are provided over tointersect both movable body 20 and fixing body 40 in the vibrationdirection.

In the present embodiment, as illustrated in FIG. 3 to FIG. 9 , elasticsupport parts 81 and 82 are attached parallel to each other over bothend portions (upper and lower end portions) of coil holding part 42separated in the vibration direction, and both end portions of themovable body 20.

Elastic support parts 81 and 82 are formed in a circular plate-shape inwhich annular inner periphery part 802 serving as an inner spring endportion and annular outer periphery part 806 serving as outer spring endportion are joined by elastically deformable deformation arm 804 with anarc shape in plan view.

Deformation arm 804 is disposed in a spiral shape that connects innerperiphery part 802 and outer periphery part 806, and inner peripherypart 802 and outer periphery part 806 are relatively displaced in theaxial direction through deformation of deformation arm 804.

Elastic support parts 81 and 82 support movable body 20 so as to bemovable in the axial direction (the vibration direction) without makingcontact with fixing body 40.

Elastic support parts 81 and 82 are a plurality of plate-shaped leafsprings. Movable body 20 may have a plurality of elastic support parts81 and 82 as three or more leaf springs. The plurality of leaf springsis attached along the direction orthogonal to the vibration direction.

Note that even in the case where movable body 20 is driven (vibrated),or an external impact is received, elastic support parts 81 and 82 makecontact with inner peripheral surface 42 a of cylindrical main body part422 of movable body 20 without making contact with the pair of coils 61and 62, and thus they are not damaged. In addition, elastic supportparts 81 and 82 may be composed of any parts as long as they movablyelastically support movable body 20. In the present embodiment, elasticsupport parts 81 and 82 are members with the same configurations.

Inner periphery part 802 includes connection hole 802 a disposed at acenter of elastic support parts 81 and 82. Both end portions (connectingparts 31 and 33 support fixing parts 314 and 334) of movable body 20separated in the vibration direction are fit and connected to connectionhole 802 a. Inner periphery part 802 is fit in a sandwiching manner inthe direction orthogonal to the protruding direction of support fixingparts 314 and 334.

On the other hand, outer periphery part 806 is attached to the upper andlower end portions of coil holding part 42, i.e., opening edge surfaces427 a and 428 a of end flange parts 427 and 428. Outer periphery part806 may be fixed to opening edge surfaces 427 a and 428 a of end flangeparts 427 and 428 by being bonded and the like to opening edge surfaces427 a and 428 a with an adhesive agent and the like. In addition, outerperiphery part 806 may be fixed in a sandwiched manner between openingedge surfaces 427 a and 428 a and positioning surface parts 128 and 118of case 10 side with engaging protruding parts 44 and 45 positioned andengaged with positioning groove part 808. In the present embodiment,outer periphery part 806 is fixed in a sandwiched state between openingedge surfaces 427 a and 428 a and positioning surface parts 128 and 118of case 10 side.

The leaf springs serving as elastic support parts 81 and 82 may beformed of any elastically-deformable materials, and may be formed bysheet metal processing using a stainless-steel sheet, a phosphor bluecopper and the like. In the present embodiment, elastic support parts 81and 82 are composed of thin disc-shaped spiral springs formed ofphosphor blue copper with high workability, high corrosion resistance,and high pull strength and wear resistance. In addition, by forming itwith non-magnetic substances such as phosphor blue copper, the magneticflux flow of the magnetic circuit is not disrupted at all. Elasticsupport parts 81 and 82 may be formed of resin as long as movable body20 is support such that it can be vibrated. In addition, elastic supportparts 81 and 82 has a plate shape and thus can achieve improvement ofpositional accuracy, i.e., improvement of processing accuracy incomparison with cone shaped springs.

In the present embodiment, the plurality of elastic support parts 81 and82 are joined to coil holding part 42 and movable body 20 with the samespiral direction.

In this manner, in the present embodiment, as the plurality of elasticsupport parts 81 and 82, a plurality of spiral leaf springs is used inthe same spiral direction, and attached to both end portions separatedin the vibration direction in movable body 20 so as to elasticallysupport movable body 20 with respect to fixing body 40.

In this manner, when the movement amount of movable body 20 isincreased, the movable body 20 moves in the translation direction (here,the direction on the plane perpendicular to the vibration direction)while being rotated although this movement is slight. When the spiraldirections of the plurality of leaf springs are opposite directions, theplurality of leaf springs move in the buckling direction or the pullingdirection, and smooth movement is hindered.

In the present embodiment, elastic support parts 81 and 82 are fixed tomovable body 20 such that the spiral directions are the same direction,and thus, even when the movement amount of movable body 20 is increased,smooth movement, i.e., deformation, along the vibration direction can beachieved. Thus, a larger amplitude can be achieved, and the vibrationoutput can be increased. It should be noted that, depending on thedesired vibration range of movable body 20, the spiral directions of theplurality of elastic support parts 81 and 82 may be opposite to eachother.

Plate-shaped elastic support parts 81 and 82 are disposed such thatinner periphery parts 802 of elastic support parts 81 and 82 overlapspring fixing parts 313 and 333 of the end portion of movable body 20 inthe vibration direction with respect to movable body 20. Note that itmay be joined to inner periphery part 802 with an adhesive agent and thelike applied to spring fixing parts 313 and 333. In this case, springfixing parts 313 and 333 may be firmly joined to inner periphery part802 through an adhesive agent retained in a cutout formed in an arcshape around inner periphery part 802.

In addition, outer periphery part 806 of elastic support part 81 ispositioned and fixed on annular opening edge surface 427 a of end flangepart 427 while avoiding engaging protruding part 44. On the other hand,outer periphery part 806 of elastic support part 82 is positioned andfixed on annular opening edge surface 428 a of end flange part 428 whileavoiding engaging protruding part 45.

In this manner, with opening edge surfaces 427 a and 428 a of upper andlower opening edge parts of coil holding part 42 and lid part 12 andbottom part 114 of case 10, elastic support parts 81 and 82 aresandwiched in the direction orthogonal to the vibration direction.

In addition, elastic support parts 81 and 82 are attached to coilholding part 42 and movable body 20 housed inside coil holding part 42so as to close the upper and lower openings of coil holding part 42 withthe pair of coils 61 and 62 wound on the outer circumference side.

Elastic support parts 81 and 82 fit connection hole 802 a of innerperiphery part 802 to support fixing parts 314 and 334 of the upper andlower end portions of movable body 20. Then, positioning groove part 808are engaged with protruding parts 44 and 45, and outer periphery part806 is fixed in contact with opening edge surfaces 427 a and 428 a ofcoil holding part 42. In this manner, drive unit 15 in which thepositional relationship between the coil (the pair of coils 61 and 62)and movable body 20 is defined is configured, and it can be easilydisposed in case 10.

Case 10

FIG. 12 is a top surface side perspective view of case main body 11, andFIG. 13 is a bottom surface side perspective view of lid part 12.

As illustrated in FIG. 1 to FIG. 4 , FIG. 12 , and FIG. 13 , case 10houses drive unit 15 by closing opening 115 of bottomed cylindrical casemain body 11 with lid part 12.

Case main body 11 is formed by closing one opening of cylindricalperipheral wall part 112 with bottom part 114. Cutout part 113 with ashape obtained by cutting out opening 115 side that is the other openingis provided at peripheral wall part 112.

Lid part 12 and bottom part 114 in case 10 make up top surface part 122and bottom surface part (bottom part 114) of vibration actuator 1 in thepresent embodiment, and are disposed opposite to movable body 20 ofdrive unit 15 in the vibration direction of movable body 20 with apredetermined distance therebetween. Lid part 12 extends downward from apart of the outer periphery part, and includes downward part 124 thatengages with cutout part 113 of case main body 11.

As illustrated in FIG. 2 and FIG. 3 , bottom part 114 includesventilation hole 116 that emits compression air formed by thereciprocation of movable body 20 to the outside.

Ventilation hole 116 extends through the outer periphery part of bottompart 114. In case main body 11, ventilation hole 116 is formed at aposition opposite to cutout part 113 with respect to the central axistherebetween. In other words, in vibration actuator 1, the positionwhere terminal tying part 43 protrudes from the outer periphery islocated on the opposite side with respect to the axis therebetween.

In addition, ventilation hole 116 is provided at a location wheremovable body 20 does not strike even when movable body 20 is displacedand elastic support parts 81 and 82 are deformed due to an externallarge load applied to case 10 due to dropping of the actuator itself andthe like. In addition, ventilation hole 116 is provided at the cornerportion with a high strength where bottom part 114 and peripheral wallpart 112 are joined in case 10. Case 10 including ventilation hole 116in this manner can also prevent deformation of case 10 due to exertionof a large load.

Lid part 12 and bottom part 114 define the movable range of movable body20 of drive unit 15. Cone-shaped (inverted truncated cone-shaped)recesses 122 b and 114 b are provided at top surface part 122 of lidpart 12 and the rear surface of bottom part 114 of case main body 11,respectively. The tilted peripheral surfaces of recesses 122 b and 114 bare formed along the deformation state of elastic support parts 81 and82.

Together with the internal space of end flange parts 427 and 428 thatopen in the vibration direction of the housed drive unit 15, recesses122 b and 114 b define the movable space of movable body 20 and elasticsupport parts 81 and 82. Note that movable body 20 is driven in thismovable space, and this movable space is a space of a range where theplastic deformation of elastic support parts 81 and 82 does not occur.Thus, even in the case where a force exceeding the movable range isapplied to movable body 20, elastic support parts 81 and 82 make contactwith fixing body 40 (at least one of lid part 12 and bottom part 114)without causing plastic deformation, and thus the reliability can beincreased with no damage to elastic support parts 81 and 82.

At bottom part 114 of case main body 11 and the surface of top surfacepart 122 of lid part 12, center portions 114 a and 122 a are swollen ina planar fashion.

In addition, the rear surface of bottom part 114 illustrated in FIG. 12includes positioning surface part 118 provided upright from the outerperiphery, and engaging recess 117 formed with a predetermined distancebetween positioning surface parts 118.

The rear surface of top surface part 122 illustrated in FIG. 13 includespositioning surface part 128 provided upright from the outer periphery,and engaging recess 127 formed with a predetermined distance betweenpositioning surface parts 128.

In addition, at outer peripheral surface of top surface part 122,fitting protrusion 126 that radially protrudes and fits to opening 115of case main body 11 is provided.

When attaching lid part 12 to case main body 11, drive unit 15 isinserted into case main body 11. At this time, drive unit 15 ispositioned and housed inside case main body 11 by engaging protrudingpart 45 with engaging recess 117 while inserting terminal drawing part46 into cutout part 113.

In addition, positioning surface part 118 sandwiches outer peripherypart 806 of elastic support part 82 between it and opening edge surface428 a of end flange part 428. Next, while fitting downward part 124 oflid part 12 in cutout part 113, top surface part 122 is inserted intoopening 115 and closed. At this time, engaging protruding part 44engages with engaging recess 127 and positioning surface part 128sandwiches outer periphery part 806 of elastic support part 81 betweenit and opening edge surface 427 a of end flange part 427. By closing thegap between fitting protrusions 126 with a bonding material or the likewith fitting protrusion 126 in contact with the inner peripheral surfaceof opening 115, lid part 12 is fixed to case main body 11.

In the present embodiment, downward part 124 and terminal drawing part46 of coil holding part 42 are disposed in cutout part 113 of case 10,and it is closed with terminal drawing part 46 and downward part 124. Inthis manner, terminal tying part 43 is disposed to protrude outward fromthe outer peripheral surface of case 10, and vibration actuator 1 makesit easier to perform connection with the external device throughterminal tying part 43.

Operation of Vibration Actuator 1

With reference to FIG. 14 to FIG. 18 , an operation of a magneticcircuit of vibration actuator 1 is described below. FIG. 14 is a diagramschematically illustrating a magnetic circuit of the vibration actuator.FIG. 15 to FIG. 18 are diagrams illustrating an operation of theactuator main body, FIG. 15 is a diagram illustrating a vibration statewhere the movable body is located on the first amplitude position on thetop surface side, and FIG. 16 is a diagram illustrating a vibrationstate where the movable body is located at the second amplitude positionon the top surface side. In addition, FIG. 17 is a diagram illustratingthe vibration state where the movable body is located at the firstamplitude position on the bottom surface side, and FIG. 18 is a diagramillustrating an operation of the actuator main body, and is a diagramillustrating a vibration state where the movable body is located at thesecond amplitude position on the bottom surface side. Note that thesecond amplitude position illustrated in FIG. 16 and FIG. 18 is themaximum amplitude position of the movable body in the vibrationdirection.

An operation of vibration actuator 1 is described with an example wheremagnet 21 is magnetized such that front surface 21 a side as one side(in the present embodiment, the upper side) of the magnetizationdirection is N pole, and rear surface 21 b side as the other side (inthe present embodiment, the lower side) of the magnetization directionis S pole.

In vibration actuator 1, movable body 20 can be regarded as a mass partof in a vibration model of in a spring-mass system, and therefore whenthe resonance is sharp (when there is a sharp peak), the sharp peak issuppressed by attenuating the vibration. By attenuating the vibration,the resonance becomes not sharp, and the maximum amplitude value and themaximum movement amount of movable body 20 during the resonance do notvary, and thus, vibration with a suitable and stable maximum movementamount is output.

In vibration actuator 1, the pair of coils 61 and 62 are disposed suchthat the coil axis is orthogonal to the magnetic flux from first yoke 23and second yoke 25 sandwiching magnet 21 in the vibration direction.

More specifically, magnetic flux flow mf emitted from front surface 21 aside of magnet 21, transmitted from first yoke 23 to coil 61 sidethrough outer yoke 50 and coil 62 so as to impinge on magnet 21 fromsecond yoke 25 on the lower side of magnet 21 is formed.

Thus, when energization is performed as illustrated in FIG. 14 , theLorentz force of the −f direction is generated at the pair of coils 61and 62 by the interaction of the magnetic field of magnet 21 and thecurrent flowing through the coil (the pair of coils 61 and 62) inaccordance with Fleming's left hand rule.

The Lorentz force of the −f direction is the direction orthogonal to thedirection of the magnetic field and the direction of the current flowingthrough the coil (the pair of coils 61 and 62). The coil (the pair ofcoils 61 and 62) is fixed to fixing body 40 (coil holding part 42), andtherefore a force opposite to the Lorentz force of the −f direction isgenerated as the thrust of the F direction at movable body 20 includingmagnet 21 in accordance with the action-reaction law. In this manner,movable body 20 side including magnet 21 moves to the F direction, i.e.,lid part 12 (top surface part 122 of lid part 12) side (see FIG. 15 andFIG. 16 ).

In addition, when the energization direction of the pair of coils 61 and62 is switched to the opposite direction and the pair of coils 61 and 62is energized, the Lorentz force of the opposite f direction is generated(see FIG. 14 ). Due to the generation of the Lorentz force of the fdirection, a force opposite to the Lorentz force of the f direction isgenerated as a thrust (the thrust of the −F direction) at movable body20 in accordance with the action-reaction law, and movable body 20 movesto the −F direction, i.e., bottom part 114 side of case main body 11(see FIG. 17 and FIG. 18 ).

In vibration actuator 1, in a non-energized and in a non-vibrationstate, a magnetic attractive force acts between magnet 21 and outer yoke50 and functions as a magnetism spring. With the magnetic attractiveforce generated between magnet 21 and outer yoke 50 and the restorationforce of restoring the original shape of elastic support parts 81 and82, movable body 20 is returned to the original position.

Effect

In vibration actuator 1, movable body 20 includes circular plate-shapedmagnet 21, a pair of annular first yoke 23 and second yoke 25, a pair ofweight parts 27 and 29, and connecting parts 31 and 33. In front surface21 a and rear surface 21 b of magnet 21 in the axis direction, the pairof annular first yoke 23 and second yoke 25 with yoke openings(apertures) 232 and 252 at the center, and the pair of weight parts 27and 29 with through holes 272 and 292 are stacked. Through holes 272 and292 are contiguous with yoke openings (apertures) 232 and 252,respectively, in the axial direction. In the contiguous yoke openings(apertures) 232 and 252 and through holes 272 and 292, the other endportions of connecting parts 31 and 33 for connecting the pair ofelastic support parts 81 and 82 on one end portion side are disposed.

In this manner, by only attaching connecting parts 31 and 33 withrespect to magnet 21 with opening 232 of the pair of annular first yokes23, opening 252 of second yoke 25, and through holes 272 and 292 of thepair of weight parts 27 and 29 as positioning reference, movable body 20with each member favorably disposed on the axis line can be accuratelyassemble.

In addition, in the present embodiment, the outer diameter of first yoke23 and second yoke 25 is the same outer diameter as the outer diameterof magnet 21.

Thus, first yoke 23 and second yoke 25 are stacked with the outerdiameter matching the outer diameter of magnet 21, and openings 232 and252 to which connecting parts 31 and 33 are inserted can be set at thecenter portions of front and rear surfaces 21 a and 21 b of magnet 21.In this manner, connecting parts 31 and 33 can be easily installed onthe axis line of magnet 21, i.e., the axis line of movable body 20. Inthis manner, each member making up movable body 20 is assembled so as tobe located on the central axis of movable body 20, i.e., the axis in thevibration direction with magnet 21 at the center at all times.

In addition, non-magnetic substance weight parts 27 and 29 are insertedoutside connecting parts 31 and 33 and stacked at first yoke 23 andsecond yoke 25. Weight parts 27 and 29 are stacked to magnet 21 andfirst yoke 23 and second yoke 25 at a position that does not face outeryoke 50 in fixing body 40 when the vibration direction of movable body20 is at the maximum amplitude position (see FIG. 16 and FIG. 18 ). Thissuppresses the increase in the size of the configuration of the magneticcircuit of vibration actuator 1, and the magnetic circuit is formed in acompact size with high magnetic efficiency. In addition, weight parts 27and 29 composed of a non-magnetic substance can increase the degrees offreedom in design of weight parts 27 and 29 when obtaining a desiredvibration characteristics for movable body 20. Adjustment throughadding, change and the like of weights 27 and 29 with different massescan be easily performed, and in this manner, desired vibrationcharacteristics can be obtained.

According to the present embodiment, movable body 20 can be manufacturedwith high dimensional accuracy, and in turn, generation of suitablevibration output can be achieved for driving it while achievingdownsizing as vibration actuator 1.

FIG. 19 is a diagram schematically illustrating a magnetism balance ofthe vibration actuator in a non-vibration state of the presentembodiment. Vibration actuator 1 includes fixing body 40 including thepair of coils 61 and 62, and movable body 20 disposed on the inside inthe radial direction of the pair of coils 61 and 62 and including magnet21 magnetized in axis direction of the pair of coils 61 and 62.Additionally, vibration actuator 1 includes plate-shaped elastic supportparts 81 and 82 that elastically holds movable body 20 such that it ismovable in the vibration direction as the coil axial direction.

The pair of coils 61 and 62 is disposed at the outer periphery ofcylindrical main body part 422 of coil holding part 42, and outerperipheral surface 20 a of movable body 20 is disposed on the innerperiphery side of cylindrical main body part 422 with a predetermineddistance therebetween. The outer peripheral surfaces of the pair ofcoils 61 and 62 are surrounded by outer yoke 50. Elastic support parts81 and 82 support movable body 20 such that it does not makes contactwith cylindrical main body part 422. Together with magnet 21, first yoke23, second yoke 25 and coils 61 and 62, outer yoke 50 forms a magneticpath.

Here, outer yoke 50 includes the plurality of openings 53 and 55dispersed in the circumferential direction at the same position in thevibration direction. Openings 53 and 55 are formed to keep balance ofthe magnetic path configured together with magnet 21 and coils 61 and 62in the circumferential direction.

With this configuration, in vibration actuator 1, during the non-drivingillustrated in FIG. 19 , movable body 20 including magnet 21 is equallyattracted in left and right upper and lower directions with respect tofixing body 40 including outer yoke 50 provided with the plurality ofopenings 53 and 55 through generation of magnetic attractive force J1.That is, with outer yoke 50 and magnet 21 functioning as magnetismspring, movable body 20 is disposed in a balanced state with respect tofixing body 40.

Then, when moving in one direction (F direction) of the vibrationdirection within the height of outer yoke 50 (the length range of thevibration direction), movable body 20 is equally attracted in the leftand right directions on the upper side with left and right magneticattractive force J1 on the upper side of movable body 20 as illustratedin FIG. 15 . In this manner, in the vibration state where movable body20 is located at the first amplitude position on the top surface side asthe vibration state within the height range up to the upper end of outeryoke 50, movable body 20 moves straight in one direction of thevibration direction, here, the F direction.

Next, movable body 20 is set to a state where it is further moved to onedirection (F direction) and protruded from outer yoke 50, i.e., a statewhere it is moved to a position where one end portion of movable body 20protrudes from outer yoke 50 as illustrated in FIG. 16 .

When this state is the vibration state where movable body 20 is locatedat the second amplitude position on the top surface side, i.e., themaximum amplitude position on the top surface side, the magneticattractive force is not generated at the left and right ends of movablebody 20 on the upper and lower sides. In this manner, the vibrationstate where it is located on the second amplitude position on the topsurface side, movable body 20 and fixing body 40 do not attract eachother, and the left and right magnetism balance of movable body 20 isensured. The movement of movable body 20 in this state is straightmovement in the vibration direction.

On the other hand, when the energization direction of coils 61 and 62becomes opposite, it moves within the height of outer yoke 50 (thelength range in the vibration direction) in the other direction (−Fdirection) of the vibration direction. In this case, as illustrated inFIG. 17 , movable body 20 is equally attracted in the left and rightdirections on the lower side with left and right magnetic attractiveforce J1 on the lower side of movable body 20. In this manner, in thevibration state where movable body 20 is located at the first amplitudeposition on the bottom surface side as the vibration state within thevibration range to the lower end of outer yoke 50, movable body 20 movesstraight in the other direction of the vibration direction, here, the −Fdirection.

Next, movable body 20 further moves to the other direction (−Fdirection), and the state where it is protruded from outer yoke 50,i.e., the state where it is moved to the position where the other endportion of movable body 20 is protruded from outer yoke 50 asillustrated in FIG. 18 . When this state is set as the vibration statewhere movable body 20 is located at the second amplitude position on thebottom surface side, i.e., the bottom surface side maximum amplitudeposition, the magnetic attractive force is not generated at the left andright ends on the upper and lower sides of movable body 20. In thismanner, in the vibration state where movable body 20 is located at thesecond amplitude position on the bottom surface side, movable body 20and fixing body 40 do not attract each other, and the left and rightmagnetism balance of movable body 20 is ensured. The vibration ofmovable body 20 in this state is straight movement in the vibrationdirection.

In this manner, in vibration actuator 1, regardless of the position ofmovable body 20 displaced due to the vibration, i.e., the vibrationstate of the first and second amplitude positions on the top surfaceside or first and the vibration state of second amplitude positions onthe bottom surface side, vibration is favorably made with a goodmagnetism balance. The magnetism balance is achieved with outer yoke 50including the plurality of openings 53 and 55 dispersed in thecircumferential direction at the same position in the vibrationdirection, such that the magnetic path configured together with magnet21 and coils 61 and 62 is balanced in the circumferential direction.

Here, with the comparative examples illustrated in FIG. 20 and FIG. 21 ,effects of the vibration actuator are described in more detail. FIG. 20is a diagram illustrating a magnetism balance in a non-vibration stateof the vibration actuator of the comparative example of the case whereone opening is provided in the outer yoke. FIG. 21A and FIG. 21B arediagrams illustrating an operation of a vibration actuator as acomparative example, FIG. 21A is a diagram illustrating a vibrationstate where the movable body is located on the first amplitude positionon the top surface side, and FIG. 21B is a diagram illustrating avibration state where the movable body is located at the secondamplitude position on the top surface side.

Vibration actuator 1A illustrated in FIG. 20 is a vibration actuator asa comparative example that is different from vibration actuator 1 of theembodiment only in the configuration of outer yoke 50A. That is, invibration actuator 1A illustrated in FIG. 20 and FIG. 21 , outer yoke50A includes only opening 53, and does not include other openings 55unlike outer yoke 50 of vibration actuator 1.

As with vibration actuator 1, in vibration actuator 1A, magneticattractive force J2 is generated at the left right end parts on theupper and lower sides of movable body 20A during the non-driving asillustrated in FIG. 20 . That is, magnetic attractive force J2 isgenerated between fixing body 40A and the radial end portions (the upperand lower left and right end portions) of the both end portionsseparated in the vibration direction.

In this manner, during the non-driving of vibration actuator 1A, movablebody 20A is equally attracted to fixing body 40A side in the upper andlower directions on the left and right sides, and movable body 20A islocated in the state where the magnetism is balanced with respect tofixing body 40A.

In vibration actuator 1A having the above-mentioned configuration, themagnetism balance is changed when the movable body is vibrated incomparison with the vibration actuator 1 of the present embodiment.

In vibration actuator 1A, when movable body 20A moves in one direction(F direction) of the vibration direction, it is set to the vibrationstate where it moves within the height of outer yoke 50A (the lengthrange of the vibration direction) as illustrated in FIG. 21A. This stateis the state where movable body 20A is located at the first amplitudeposition on the top surface side, and left and right magnetic attractiveforce J2 is generated on the upper side of movable body 20A and equallyattracted to each other. On the other hand, on the lower side of movablebody 20A, right side magnetic attractive force J3 is generated on thelower side of movable body 20A since outer yoke 50A includes onlyopening 53 (left side opening in FIG. 21 ). On the lower side of movablebody 20A, left and right magnetism balances are different from eachother as illustrated in FIG. 21A. For example, the magnetic attractiveforce on the side (in the drawing, left side) on which opening 53 islocated with movable body 20 at the center is ½ of the magneticattractive force on the side (in the drawing, the right side) on whichthe opening is not provided.

Next, movable body 20A further moves to one direction (F direction) andprotruded from outer yoke 50A, i.e., it is moved to a position where oneend portion of movable body 20A is protruded from outer yoke 50A ofmovable body 20A. As illustrated in FIG. 21B, this state is a statewhere it is located at the second amplitude on the top surface partside, and magnetic attractive force J3 is generated only at the lowerright portion of movable body 20A, and movable body 20A is attracted tofixing body 40A only at that portion.

In this manner, a force of rotating in the arrow U is generated atmovable body 20A, and movable body 20 cannot be vibrated straight in thevibration direction.

In this manner, in the vibration actuator 1 of the present embodiment,suitable vibration output can be generated while achieving thedownsizing with a good magnetism balance regardless of the position ofmovable body 20 displaced due to the vibration in comparison withvibration actuator 1A.

Further, vibration actuator 1 has the structure in which drive unit 15is housed in case 10, and thus the outer peripheral surface ofperipheral wall part 112 of case 10 can be smoothed. In this manner,when attaching vibration actuator 1 to an electric apparatus, it ispossible to increase the joining state and the joining strength of amember, such as a double-sided tape, used for bonding a buffer membersuch as sponge to be interposed between it and an attaching portion tothe outer peripheral surface.

In addition, since ventilation hole 116 is provided in the case, the airhaving nowhere to go during the vibration of movable body 20 in case 10can be discharged to the outside, and the vibration itself of movablebody 20 can be prevented from being attenuated. In addition, entry offoreign matters can be prevented, and suitable sensory vibration can begenerated with high output.

Since the pair of coils 61 and 62 is disposed at the outer peripheralsurface of coil holding part 42, it is not necessary to pull out the endportion of the winding coil line to the outside for connection to theexternal device at the time of assembly in comparison with the casewhere it is disposed at the inner peripheral surface of coil holdingpart 42.

In addition, since vibration actuator 1 is configured with drive unit 15disposed in case 10, elastic support parts 81 and 82 that require highdimensional accuracy can be fixed through assembling to coil holdingpart 42.

That is, drive unit 15 is formed by housing movable body 20 in coilholding part 42 and assembling elastic support parts 81 and 82. In thismanner, the installation of movable body 20, which includes fixation ofelastic support parts 81 and 82, can be determined with coil holdingpart 42 as a reference, and the accuracy of the direction of thevibration generated as a product can be increased.

Specifically, for example, by only increasing the dimensional accuracyof coil holding part 42 formed as one component using resin or the like,coils 61 and 62 and magnet 21 of movable body 20 attached throughelastic support parts 81 and 82 can be disposed in a precise positionalrelationship. That is, vibration actuator 1 that stably vibrates can beeasily manufactured.

In addition, case 10 is formed in a bottomed cylindrical shape, i.e.,formed with cup-shaped case main body 11 and lid part 12. In thismanner, in comparison with a configuration in which peripheral wall part112 and bottom part 114 are separately provided, the number ofcomponents can be reduced, assemblability can be improved, and impactresistance can be improved.

When lid part 12 is fit to opening 115 of cup-shaped case main body 11,fitting protrusion 126 is fit between fitting protrusions 126 separatedin the circumferential direction in the state where the arc slit isformed with respect to inside opening 115. Through welding to fill thearc slit, filling the arc slit with bonding material and the like, theycan be fixed without providing a protrusion at the outer peripheralsurface of case 10.

Vibration actuator 1 is driven by alternating current waves input fromthe power supply part (for example, drive control part 203 illustratedin FIG. 22 and FIG. 23 ) to the pair of coils 61 and 62. That is, theenergization direction of the pair of coils 61 and 62 is periodicallyswitched, and the thrust in the F direction on top surface part 122 sideof lid part 12 and the thrust of the −F direction on bottom part 114side alternately act on movable body 20 as illustrated in FIG. 14 . Inthis manner, movable body 20 vibrates in the vibration direction.

In the following, the driving principle of vibration actuator 1 isbriefly described. In the vibration actuator 1 of the presentembodiment, movable body 20 vibrates with respect to fixing body 40 atresonance frequency F_(r) [Hz] calculated by Equation 1, where m [kg] isthe mass of movable body 20, and K_(sp) is the spring constant of thespring (elastic support parts 81 and 82 as springs).

$\begin{matrix}\left( {{Equation}1} \right) &  \\{F_{r} = {\frac{1}{2\pi}\sqrt{\frac{K_{sp}}{m}}}} & \lbrack 1\rbrack\end{matrix}$

Movable body 20 can be regarded as making up a mass part of in avibration model of a spring-mass system, and as such movable body 20 isput in a resonance state when alternating current waves of a frequencyequal to resonance frequency F_(r) of movable body 20 is input to thecoil (the pair of coils 61 and 62). That is, movable body 20 can beefficiently vibrated by inputting alternating current waves of afrequency substantially equal to resonance frequency F_(r) of movablebody 20 from the power supply part to the coil (the pair of coils 61 and62).

An equation of motion and a circuit equation representing the drivingprinciple of vibration actuator 1 are described below. Vibrationactuator 1 is driven based on the equation of motion represented byEquation 2 and the circuit equation represented by Equation 3.

$\begin{matrix}\left( {{Equation}2} \right) &  \\{{m\frac{d^{2}{x(t)}}{{dt}^{2}}} = {{K_{f}{i(t)}} - {K_{sp}{x(t)}} - {D\frac{{dx}(t)}{dt}}}} & \lbrack 2\rbrack\end{matrix}$

M: mass [kg]X(t): displacement [m]K_(f): thrust constant [N/A]I(t): current [A]K_(sp): spring constant [N/m]D: attenuation coefficient [N/(m/s)

$\begin{matrix}\left( {{Equation}3} \right) &  \\{{e(t)} = {{{Ri}(t)} + {L\frac{{di}(t)}{dt}} + {K_{e}\frac{{dx}(t)}{dt}}}} & \lbrack 3\rbrack\end{matrix}$

E(t): voltage [V]R: resistance [Ω]L: inductance [H]K_(e): counterelectromotive force constant [V/(rad/s)]

That is, mass m [kg], displacement x(t) [m], thrust constant K_(f)[N/A], current i(t) [A], spring constant K_(sp) [N/m], attenuationcoefficient D [N/(m/s)] and the like in vibration actuator 1 can beappropriately changed as long as Equation 2 is satisfied. In addition,voltage e(t) [V], resistance R[Ω], inductance L [H], andcounterelectromotive force constant K_(e) [V/(rad/s)] can beappropriately changed as long as Equation 3 is satisfied.

In this manner, in vibration actuator 1, large vibration output can beefficiently obtained when coils 61 and 62 are energized with alternatingcurrent waves corresponding to resonance frequency F_(r) determined bymass m of movable body 20 and spring constant K_(sp) of elastic supportparts 81 and 82 as leaf springs.

In addition, vibration actuator 1 is driven by the resonance phenomenonusing the resonance frequency represented by Equation 1 and satisfyingEquations 2 and 3. In this manner, vibration actuator 1 can be drivenwith low power consumption, i.e., movable body 20 can be vibratedstraight with low power consumption. In addition, when attenuationcoefficient D is increased, vibration can be generated over a higherbandwidth.

According to the present embodiment, plate-shaped elastic support parts81 and 82 are disposed on the upper and lower (the vibration direction)sides of movable body 20. In this manner, vibration actuator 1 canstably drive movable body 20 in the vertical direction while efficientlydistributing the magnetic flux of the pair of coils 61 and 62 fromelastic support parts 81 and 82 on the upper and lower sides of magnet21. In this manner, as vibration actuator 1, high output vibration canbe achieved.

In addition, fixing body 40 includes coil holding part 42 that servesalso as a protective function of the pair of coils 61 and 62 for movablebody 20. In this manner, even in the case where fixing body 40 receivesimpacts, it can resist the impact, and damages such as deformation arenot given to elastic support parts 81 and 82. In addition, the impact istransmitted to the pair of coils 61 and 62 through cylindrical main bodypart 422 made of resin, and thus damages can be suppressed, achievinghighly reliable vibration actuator 1. In this manner, with vibrationactuator 1, downsizing can be achieved in a cost-effective manner, andsuitable sensory vibration can be generated with impact resistance andhigh output.

Electronic Apparatus

FIG. 22 and FIG. 23 are diagrams illustrating an example of mounting ofvibration actuator 1. FIG. 22 illustrates an example in which vibrationactuator 1 is mounted in game controller GC, and FIG. 23 illustrates anexample in which vibration actuator 1 is mounted in mobile terminal M.

Game controller GC is connected to a game machine main body throughwireless communications, and used by being grabbed by the user, forexample. Here, game controller GC has a rectangular plate shape, and theuser operates game controller GC by grabbing its left and right sideswith both hands.

Game controller GC notifies the user of commands from game machine mainbody in the form of vibration. Note that although not illustrated in thedrawings, game controller GC has functions other than commandnotification, such as an inputting operation part to the game machinemain body.

Mobile terminal M is a mobile communication terminal such as a mobilephone and a smartphone, for example. Mobile terminal M notifies the userof incoming calls from external communication apparatus in the form ofvibration, and achieves each function (such as a function of providingsense of operation and a function of providing realism) of mobileterminal M.

As illustrated in FIG. 22 and FIG. 23 , each of game controller GC andmobile terminal M includes communication part 201, processing part 202,drive control part 203, and vibration actuators 204, 205 and 206 thatare vibration actuator 1 as a driving part. Note that a plurality ofvibration actuators 204 and 205 are mounted in game controller GC.

In game controller GC and mobile terminal M, it is preferable thatvibration actuators 204 to 206 be disposed such that the main surface ofthe terminal and the surface orthogonal to the vibration direction ofvibration actuators 204 to 206, here, the bottom surface of bottom part114 are parallel to each other, for example.

The main surface of the terminal is a surface that makes contact withthe body surface of the user, and, in the present embodiment, means avibration transmission surface that makes contact with the body surfaceof the user and transmits vibration thereto. Note that the main surfaceof the terminal and the bottom surface of bottom part 114 of vibrationactuators 204, 205 and 206 may be disposed to be orthogonal to eachother.

More specifically, vibration actuators 204 and 205 are mounted in gamecontroller GC such that the surface that makes contact with thefingertip, finger ball, palm and the like of the user operating it, orthe surface where the operation part is provided, and the vibrationdirection are orthogonal to each other. In addition, in the case ofmobile terminal M, vibration actuator 206 is mounted such that displayscreen (touch panel surface) and the vibration direction are orthogonalto each other. In this manner, the vibration in the directionperpendicular to game controller GC and the main surface of mobileterminal M is transmitted to the user.

Communication part 201, which is connected to the external communicationapparatus through wireless communication, receives signals from thecommunication apparatus and outputs it to processing part 202. In thecase of game controller GC, the external communication apparatus is agame machine main body as an information communication terminal, andperforms communication in accordance with short-range wirelesscommunication standard such as Bluetooth (registered trademark). In thecase of mobile terminal M, the external communication apparatus is abase station, and performs communication in accordance with the movingbody communication standard, for example.

Processing part 202 converts the input signal into a driving signal fordriving vibration actuators 204, 205 and 206 with the conversion circuitpart (omitted in the drawing), and outputs it to drive control part 203.Note that in mobile terminal M, processing part 202 generates drivingsignals on the basis of signals input from communication part 201, andsignals input from various functional parts (e.g., an operation partsuch as a touch panel omitted in the drawing).

Drive control part 203 is connected to vibration actuators 204, 205 and206, and the circuit for driving vibration actuators 204, 205 and 206 ismounted. Drive control part 203 supplies the driving signal to vibrationactuators 204, 205 and 206.

Vibration actuators 204, 205 and 206 are driven in accordance with thedriving signal from drive control part 203. More specifically, invibration actuators 204, 205 and 206, movable body 20 vibrates in thedirection orthogonal to the main surface of mobile terminal M and gamecontroller GC.

Note that movable body 20 may make contact with bottom part 114 or topsurface part 122 of lid part 12 with a damper therebetween each time itvibrates. In this case, in association with the vibration of movablebody 20, the impact on bottom part 114 or top surface part 122 of lidpart 12, i.e., the impact on the housing, is directly transmitted to theuser as vibration.

The vibration in the direction perpendicular to the body surface istransmitted to the body surface of the user that makes contact with gamecontroller GC or mobile terminal M, and thus sufficient sensoryvibration can be given to the user. In game controller GC, the sensoryvibration for the user can be given by using one or both of vibrationactuators 204 and 205, and at least highly expressive vibrations such asselectively applying strong and weak vibrations can be provided.

The invention made by the present inventor has been describedspecifically based on the above embodiments. The invention is notlimited to the above embodiments, but can be modified to the extent notto depart from the gist thereof.

In addition, the vibration actuator according to the present inventionmay be mounted in the part that makes contact with the user in mobileapparatuses other than the game controller GC and the mobile terminal M(for example, mobile information terminals such as tablet PC and mobilegame terminals) and the like. Vibration actuator 1 may be mounted on thepart in contact with the user in hand-carry electrical devices such asmobile terminals and electric beauty and beauty equipment such as facialmassagers. Vibration actuator 1 may be mounted on a part in contact withthe user in a wearable device) that is worn and used by the user. Thepart in contact with the user is, for example, a handle that the usergrasps during use, in the case of a hand-carry electrical device such asa game controller GC, for example. In the case of a wearable electricaldevice, such as a facial massager, for example, the user-contacting partis, for example, a pressurizing part that applies pressure to the user'sbody surface.

INDUSTRIAL APPLICABILITY

The vibration actuator according to the present invention can bemanufactured with high dimensional accuracy while achieving downsizingand an effect of driving with suitable vibration outputs. The vibrationactuator according to the present invention is useful for electricbeauty equipment and the like.

REFERENCE SIGNS LIST

-   1, 204, 205, 206 Vibration actuator-   10 Case-   11 Case main body-   12 Lid part-   15 Drive unit-   20 Movable body-   20 a Outer peripheral surface-   21 Magnet-   21 a Front surface-   21 b Rear surface-   23 First yoke-   25 Second yoke-   27, 29 Weight part-   31, 33 Connecting part-   40 Fixing body-   41 Layout part-   42 Coil holding part-   42 a Inner peripheral surface-   42 b, 42 c Coil attaching portion-   43 Terminal tying part-   44, 45 Engaging protruding part-   46 Terminal drawing part-   47 Connecting groove part-   50 Outer yoke-   51 Yoke main body-   52 End portion-   53, 55 Opening-   55 a Upper portion-   55 b Lower portion-   61, 62 Coil-   63, 64 Winding-   81, 82 Elastic support part-   112 Peripheral wall part-   113 Cutout part-   114 Bottom part-   114 a, 122 a Center portion-   114 b, 122 b Recess-   115 Opening-   116 Ventilation hole-   117 Engaging recess-   118 Surface part-   122 Top surface part-   122 b Recess-   124 Downward part-   126 Fitting protrusion-   127 Engaging recess-   128 Positioning surface part-   201 Communication part-   202 Processing part-   203 Drive control part-   232, 252 Yoke opening (Aperture)-   272, 292 Through hole-   312 Connection main body-   313, 333 Spring fixing part-   314 Support fixing part-   332 Connection main body-   334 Support fixing part-   412 Coil guide part-   420 Recessed part-   422 Cylindrical main body part-   426, 427, 428 Flange part-   426 a Outer periphery part-   427 a, 428 a Opening edge surface-   432 Fillet-   533 Cutout part-   802 Inner periphery part-   802 a Connection hole-   804 Deformation arm-   806 Outer periphery part-   808 Positioning groove part

1. A vibration actuator comprising: a movable body including a magnethaving a circular plate shape, wherein a pair of annular yokes includingan opening at a center and a pair of weight parts including a throughhole that is contiguous with the opening in an axial direction arestacked on a front surface and a rear surface of the magnet in the axisdirection, and another end portion of a connecting part that connects apair of elastic support parts on one end portion side is disposed in theopening and the through hole that are contiguous with each other; and afixing body including a cylindrical part configured to house the movablebody, wherein with the pair of elastic support parts, the movable bodyis supported so as to be allowed to vibrate back and forth in the axialdirection, and a pair of annular coils disposed radially outside themovable body is provided, wherein the movable body is vibrated in theaxial direction through energization of the coil.
 2. The vibrationactuator according to claim 1, wherein the opening and the through holecontiguous with each other have the same diameter.
 3. The vibrationactuator according to claim 1, wherein an outer diameter of the weightpart is smaller than an outer diameter of the yoke.
 4. The vibrationactuator according to claim 1, wherein the connecting part includes asupport fixing part on the one end portion side and a connection mainbody on the other end portion side, the support fixing part beingconfigured to connect to the elastic support part, the connection mainbody being configured to be inserted to the opening through the throughhole and joined to the through hole and the opening.
 5. The vibrationactuator according to claim 4, wherein the opening is a through holeextending through the yoke; and wherein the connection main body isjoined to the magnet in the opening.
 6. The vibration actuator accordingto claim 4, wherein the support fixing part protrudes from a surface onone end portion side of the connection main body, and has an outerdiameter smaller than an outer diameter of the connection main body. 7.The vibration actuator according to claim 6, wherein in the connectionmain body, a recess is formed around the support fixing part at aportion where the support fixing part protrudes.
 8. The vibrationactuator according to claim 7, wherein the recess is an annular groovepart that surrounds a periphery of the support fixing part.
 9. Thevibration actuator according to claim 1, wherein the weight part isstacked to the magnet and the yoke such that at the fixing body, theweight part is disposed at a position that does not face an outer yokesurrounding the coil when the movable body is located at a maximumamplitude position in the vibration direction; and wherein the weightpart comprising a non-magnetic substance.
 10. An electric apparatus thatis a hand-carry electric apparatus or a wearable electric apparatus,wherein the vibration actuator according to claim 1 is mounted at acontact part for a user.